On Wed, Jan 21, 2015, at 14:44, Denys Vlasenko wrote: > On Sun, Jan 18, 2015 at 12:45 PM, Alexander van Heukelum > <heuke...@fastmail.fm> wrote: > > KERNEL_STACK_OFFSET is the offset from the top of the kernel stack > > page to the value of the kernel_stack percpu variable. This patch > > changes KERNEL_STACK_OFFSET to configure a reserved space of 16 > > bytes above the user ptregs frame. KERNEL_STACK_OFFSET must be > > set to a multiple of 16 bytes due to the automatic stack alignment > > of interrupts, traps, and exceptions on x86_64. > > I propose to set kernel_stack percpu variable to point > to the top of kernel stack (obvious, isn't it?) > and eliminate KERNEL_STACK_OFFSET altogether.
By "top of kernel stack", do you mean the page boundary or the top of struct pt_regs on the kernel stack? (is it really that obvious?) I think Borislav did the latter for x86_64 in his patchset. Eliminating KERNEL_STACK_OFFSET was what I did in my first attempt, and I broke i386 by not thinking through what x86 common code was really doing :). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
